The responses of Petunia to simulated pollutants in chamber conditions and its uses as bioindicator of pollution
Abstract
Plants damage that results from air pollution are often confused with plant diseases, nutritional deficiency or natural senescence. Bio-indicating plants are used to obtain the direct identification of air pollutants on plants and determine the geographical distribution of pollutants. The responses of two varieties of Petunia (purple and white) to ten treatments including fumigated ozone (‘O’AOT40 28.2 ppm h), 10 µM fluoranthene ‘F’ and H2SO4 (‘A’ pH 3) mist, MQ water sprayed on plants as control ‘C’ with other mixtures were investigated in 30 d under controlled conditions. Also, a 1:1 mixture of Na2S2O3 and 1mM NaOOCCC6H5 form part of the treatments and was used as scavenging solution ‘S’ against Reactive Oxygen Species (ROS). Eco-physiological traits are leaf chlorophyll, carotenoids contents and chlorophyll fluorescence. Metal analysis was by ICP-AES, Histochemical analysis using 3’3-diaminobenzidine (DAB)-HCl, combined with Evans blue staining procedure for hydrogen peroxide deposition and dead cell portion of leaves. Plants health determined as SPAD chlorophyll values at 7, 14, 21 and 28 d of treatments (DOT) were significantly reduced after 28 DOT for the petunia . Chlorophyll depreciation ‘CD’ was > 40% in purple petunia for the ‘O’ containing treatments, < 25% for other treatments and ≈ 10% for ‘C’ whereas it ranged from 25-28% in ‘O’ containing treatments, < 20% for other treatments and 10% for ‘C’. A derivative to assess plant health status by the variation of the ratio (total chlorophyll content: carotenoids) against CD was obtained. Higher R2 value for this derivative in the white petunia suggested that though the leaf of purple petunia indicated higher sensitivity to ozone than the white, white petunia is a better bio-indicator of the stresses examined from the present study. Also, the leaf chlorophyll fluorescence showed higher significant values in the ‘O’ containing and the other treatments in the white petunia compared with the purple petunia. Metal analyses in purple petunia showed Mg and Mn from the seven metals (Al, Ca, Fe, Na, K, Mg and Mn) quantified to be significantly reduced in leaves. 'A' appears to have higher negative effects on petunia compared with other treatments. The stomatal aperture measured from SEM images for the purple petunia showed reduced aperture in the ‘O’ treatment compared with other treatments. The histochemical analysis confirmed a relatively higher H2O2 deposition and dead cell portions in the ‘O’ containing treatment than others. These results strongly suggest that the Petunia plant is sensitive to the simulated atmospheric pollutants that can be threatening to the plant health status, therefore, it can be used as a bioindicator.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2010
- Bibcode:
- 2010AGUFMGC13B0704O
- Keywords:
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- 0345 ATMOSPHERIC COMPOSITION AND STRUCTURE / Pollution: urban and regional;
- 0439 BIOGEOSCIENCES / Ecosystems;
- structure and dynamics;
- 0478 BIOGEOSCIENCES / Pollution: urban;
- regional and global;
- 1630 GLOBAL CHANGE / Impacts of global change